Prevention of tracheal cartilage injury with modified Griggs technique during percutaneous tracheostomy - Randomized controlled cadaver study

Introduction: Tracheal stenosis is the most common severe late complication of percutaneous tracheostomy causing significant decrease in quality of life. Applying modified Griggs technique reduced the number of late tracheal stenoses observed in our clinical study. The aim of this study was to investigate the mechanism of this relationship. Materials and methods: Forty-six cadavers were randomized into two groups according to the mode of intervention during 2006-2008. Traditional versus modified Griggs technique was applied in the two groups consequently. Wider incision, surgical preparation, and bidirectional forceps dilation of tracheal wall were applied in modified technique. Injured cartilages were inspected by sight and touch consequently. Age, gender, level of intervention, and number of injured tracheal cartilages were registered. Results: Significantly less frequent tracheal cartilage injury was observed after modified (9%) than original (91%) Griggs technique (p<0.001). A moderate association between cartilage injury and increasing age was observed, whereas the level of intervention (p=0.445) and to gender (p=0.35) was not related to injury. Risk of cartilage injury decreased significantly (OR: 0.0264, 95%, CI: 0.005-0.153) with modified Griggs technique as determined in adjusted logistic regression model. Discussion: Modified Griggs technique decreased the risk of tracheal cartilage injury significantly in our cadaver study. This observation may explain the decreased number of late tracheal stenosis after application of the modified Griggs method. © 2012 Akadémiai Kiadó, Budapes

From Social Data Mining to Forecasting Socio-Economic Crisis

Socio-economic data mining has a great potential in terms of gaining a better understanding of problems that our economy and society are facing, such as financial instability, shortages of resources, or conflicts. Without large-scale data mining, progress in these areas seems hard or impossible. Therefore, a suitable, distributed data mining infrastructure and research centers should be built in Europe. It also appears appropriate to build a network of Crisis Observatories. They can be imagined as laboratories devoted to the gathering and processing of enormous volumes of data on both natural systems such as the Earth and its ecosystem, as well as on human techno-socio-economic systems, so as to gain early warnings of impending events. Reality mining provides the chance to adapt more quickly and more accurately to changing situations. Further opportunities arise by individually customized services, which however should be provided in a privacy-respecting way. This requires the development of novel ICT (such as a self- organizing Web), but most likely new legal regulations and suitable institutions as well. As long as such regulations are lacking on a world-wide scale, it is in the public interest that scientists explore what can be done with the huge data available. Big data do have the potential to change or even threaten democratic societies. The same applies to sudden and large-scale failures of ICT systems. Therefore, dealing with data must be done with a large degree of responsibility and care. Self-interests of individuals, companies or institutions have limits, where the public interest is affected, and public interest is not a sufficient justification to violate human rights of individuals. Privacy is a high good, as confidentiality is, and damaging it would have serious side effects for society.Comment: 65 pages, 1 figure, Visioneer White Paper, see http://www.visioneer.ethz.c

Quantum field theory in static external potentials and Hadamard states

We prove that the ground state for the Dirac equation on Minkowski space in static, smooth external potentials satisfies the Hadamard condition. We show that it follows from a condition on the support of the Fourier transform of the corresponding positive frequency solution. Using a Krein space formalism, we establish an analogous result in the Klein-Gordon case for a wide class of smooth potentials. Finally, we investigate overcritical potentials, i.e. which admit no ground states. It turns out, that numerous Hadamard states can be constructed by mimicking the construction of ground states, but this leads to a naturally distinguished one only under more restrictive assumptions on the potentials.Comment: 30 pages; v2 revised, accepted for publication in Annales Henri Poincar

New Strong-Field QED Effects at ELI: Nonperturbative Vacuum Pair Production

Since the work of Sauter, and Heisenberg, Euler and K\"ockel, it has been understood that vacuum polarization effects in quantum electrodynamics (QED) predict remarkable new phenomena such as light-light scattering and pair production from vacuum. However, these fundamental effects are difficult to probe experimentally because they are very weak, and they are difficult to analyze theoretically because they are highly nonlinear and/or nonperturbative. The Extreme Light Infrastructure (ELI) project offers the possibility of a new window into this largely unexplored world. I review these ideas, along with some new results, explaining why quantum field theorists are so interested in this rapidly developing field of laser science. I concentrate on the theoretical tools that have been developed to analyze nonperturbative vacuum pair production.Comment: 20 pages, 9 figures; Key Lecture at the ELI Workshop and School on "Fundamental Physics with Ultra-High Fields", 29 Sept - 2 Oct. 2008, Frauenworth Monastery, Germany; v2: refs updated, English translations of reviews of Nikishov and Ritu

Zweizeitige Milzruptur am 13. postraumatischen Tag nach initial unauffällig befundener CT-Untersuchung

Delayed splenic injuries are rare but nevertheless well known and very dangerous complications after blunt abdominal trauma. The highest incidence is reported between four and eight days after trauma; however some cases with a latent period of weeks have been published. We present a case of delayed splenic rupture 13 days after trauma where most computed tomography (CT) examinations were interpreted as normal and present a review of the pathophysiology of delayed rupture, diagnosis and therapy